Container having a peelable sealing membrane, which is to receive a powder material and have excess internal pressure

ABSTRACT

A container for a powder material includes an inner portion in the form of a flange ( 13 ), and a peelable sealing membrane sealingly attached onto the flange ( 13 ) via a peripheral sealing cord ( 27 ). The sealing membrane also has at least one pull tab ( 23 ) so as to enable the peeling thereof relative to the flange ( 13 ) by breaking down the sealing cord ( 27 ). The flange ( 13 ) has at least one passageway ( 18 ) for circulating gas; the passageway ( 18 ) is to be sealed by the attached sealing membrane and is located opposite the pull tab ( 23 ) so as to release the internal excess pressure from the container ( 3 ) upon the initiation of the peeling of the sealing membrane. The container is particularly useful for eliminating, or at least reducing, the splatter of the packaged material.

The present invention relates to the field of containers, in particular of the can type, including a peelable closing membrane.

The “easy-opening” containers generally comprise a flange to form a sealing area, on which is attached a peelable closing membrane through a sealing cord (or band).

This flange is sometimes made single-piece with the container body. More often, the container is equipped with an added lid that comprises a support ring (or circle) on which is attached the peelable closing membrane, through the sealing cord. Such lids are described, for example, in the documents EP-1 878 666 or EP-1 595 808.

For that purpose, the support ring has an inner portion forming the flange; and the outer contour of the lower face of the peelable membrane is hermetically fixed to the upper face of this flange through the peripheral sealing cord.

The closing membrane is generally provided with a pull-tab for transmitting the force applied by the user (and the generated energy), in order to open the container.

This pulling action thus allows a progressive degradation of the sealing cord (peeling action), from a fracture initiation area located at this pull-tab.

This type of container is sometimes used for the packaging of powder products (also known as “pulverulent products”), for example powder baby milk, ground coffee or soluble coffee, or even any other powder dried product.

In this case, it is frequent to introduce a protective atmosphere (for example nitrogen) in the container before the closing thereof, to optimize the preservation of the packed product.

The packed product (in particular, ground coffee) is also liable to be at the origin of a gas release phenomenon (for example, carbon dioxide).

The container has thus a state of internal excess pressure.

With the present lids, at the beginning of the peeling of the closing membrane, the internal excess pressure is released very rapidly, and in an uncontrolled manner, through the central aperture defined by the flange.

Now, in practice, this gas flow through the central aperture often causes an outward expulsion of the packed powder product.

At the opening, this phenomenon is more liable to produce notably (i) a noise unexpected by the consumer and/or (ii) a pressing force on the closing membrane.

To remedy this drawback, the applicant proposes a new structure of container adapted to release the internal excess pressure at the initiation of the peeling of the peelable membrane, while limiting or eliminating the above-mentioned problems (in particular, any phenomenon of expulsion of the product).

Within this framework, the container according to the invention of the type comprising:

(i) a flange-shaped inner portion, intended to extend over the perimeter of the opening to be closed, which flange is delimited by a lower face, an upper face, an inner edge defining a central aperture and an outer edge connected to a lateral wall of the container, and (ii) a peelable closing membrane intended to close said central aperture of the ring, including an upper face and a lower face, wherein the outer contour of the lower face is hermetically fixed to the upper face of said flange through a sealing cord, which closing membrane is provided with at least one pull-tab to allow the peeling thereof with respect to said flange by degradation of said sealing cord. And according to the invention, the flange is provided with at least one passageway for the circulation of gas. This passageway is intended to be closed by the added closing membrane, and is located opposite the pull-tab to release the internal excess pressure of the container at the initiation of the peeling of said closing membrane.

According to a particular embodiment, the passageway in question consists in at least one orifice arranged through the flange, between its inner and outer edges.

In this case, the orifice(s) advantageously define together a passageway whose surface area is comprised between 0.5 and 30 mm².

The orifice(s) advantageously have a generally circular shape, whose diameter is comprised between 0.5 and 1 mm, and are 1 to 10 in number. As an alternative, the orifice(s) each consist in an elongated slot, whose length is comprised between 10 and 20 mm and whose width is comprised between 0.5 and 3 mm.

Preferably, the orifice(s) arranged in the flange are located within the footprint of the sealing cord.

This sealing cord then advantageously includes at least one not-sealed inner area in which is(are) arranged said orifice(s).

As an alternative, the gas passageway may be arranged between an inner edge of the sealing cord and an inner edge of the flange.

According to another particular embodiment, the passageway consists in a notch arranged from said inner edge of the flange and that extends towards the outer edge thereof.

Other advantageous characteristics, which can be considered independently or in combination, are described in more detail hereinafter:

-   -   the flange includes several passageways that are regularly         distributed over its circumference; this characteristic aims to         allow a random orientation of the closing membrane on the         receiving flange, while ensuring the presence of a gas         passageway at the pull-tab;     -   the inner and outer edges of the flange extend parallel, or at         least approximately parallel, relative to each other, which         provides it with constant or substantially constant width over         its whole periphery; as an alternative, the flange consists of a         peripheral annular portion continued by a disk segment (the         inner edge of the flange thus consists of a curved section         provided with a local rectilinear section, the latter being         useful notably to level a measuring-spoon).

Without this being limitative, at the gas passageway(s) arranged under the pull-tab, the sealing cord is advantageously widen to preserve a sufficient sealing force.

But in practice, the latter feature is liable to increase the level of force and energy required during the initial phase of peeling. Now, a reduced level of force and energy at the peeling initiation is one of the important elements facilitating the degradation of the sealing cord.

Within this framework, the applicant also proposes a sealing cord whose level of force and energy is reduced at the initiation of the peeling, while preserving a sufficient force for linking the closing membrane to the flange.

For that purpose, the sealing cord includes a fracture initiation area arranged at said pull-tab; this fracture initiation area comprises a protruding section of said outer edge of said sealing cord, which forms a local protuberance extending towards said outer edge of said flange. And one at least of the above-mentioned gas passageways is arranged at this fracture initiation area.

Such a structure ensures a significant reduction of the effort required at the initiation of the fracture of the sealing cord by pulling the tab of the closing membrane; and it thus facilitates the initiation/starting of the peeling of this closing membrane.

Other interesting characteristics, relating to the structure of this sealing cord, are described in more detail hereinafter:

-   -   the protruding section of the sealing cord and the pull-tab each         include an axis of symmetry, which axes of symmetry extend         coaxially, or almost coaxially, relative to each other;     -   the protruding section of the sealing cord has a generally point         shape that is defined by two outer sides diverging from an outer         end arranged on the side of the outer edge of the flange; these         divergent outer sides are advantageously rectilinear or         substantially rectilinear, and define together an angle         preferably comprised between 60° and 160°; according to a         particular embodiment, these divergent outer sides of the         protruding section of the sealing cord define together an outer         angle comprised between 10° and 90°, and said protruding section         is also delimited by two divergent inner sides, continuing said         divergent outer sides, which define together a greater inner         angle than said outer angle, comprised between 60° and 160°;     -   the fracture initiation area of the sealing cord also includes a         concave section arranged at the inner edge of said sealing cord,         opposite the protruding section of the outer edge, which forms a         local recess extending towards the outer edge of the flange; the         protruding section of the outer edge and the concave section of         the inner edge of the sealing cord are preferably complementary         to each other and extend parallel, or at least approximately         parallel, relative to each other;     -   the flange has a variable width, with an widened segment at the         fracture initiation area; in this case, the inner edge of this         flange is advantageously off-centred with respect to its outer         edge, with an offset at the opposite of the fracture initiation         area of the sealing cord, to obtain said widen flange segment.

Moreover, the container advantageously includes an added ring including—an outer portion, adapted to be fixed to an edge of the container body delimiting said opening to be closed, and—an inner portion forming the flange, intended to extend over the perimeter of said opening to be closed.

As an alternative, the flange is made single-piece with the lateral wall of the container body.

The present invention also relates to the ring for a closing lid, possibly equipped with a peelable closing membrane, as defined hereinabove.

This invention will be further illustrated, without being limited thereby, by the following description, in relation with the appended drawings in which:

FIG. 1 is a general perspective view of a container equipped with a lid according to the invention, with herein its closing membrane during peel;

FIG. 2 shows, in isolation, the lid equipping the container according to FIG. 1;

FIG. 3 is a top view of the ring constituting the lid according to FIG. 2 (without the closing membrane), whose flange is provided with the passageway for the circulation of gas and on which is shown the sealing cord;

FIG. 4 is a partial and enlarged view of the ring according to FIG. 3, showing in detail its passageway for the circulation of gas and the fracture initiation area of its sealing cord;

FIG. 5 is a top view of a second ring according to the invention, provided with a plurality of passageways for the circulation of gas;

FIG. 6 is a partial and enlarged view of a third ring according to the invention, the gas circulation passageway of which consists in several circular orifices arranged in a not-sealed area of the sealing cord;

FIG. 7 is a partial and enlarged view of a fourth ring according to the invention, the gas circulation passageway of which herein consists in a slot arranged in a not-sealed area of the sealing cord;

FIG. 8 is a partial and enlarged view of a fifth ring according to the invention, with the gas circulation passageway consisting in an orifice arranged outside the footprint of the sealing cord;

FIG. 9 is a partial and enlarged view of a sixth ring according to the invention, provided with a gas circulation passageway in the form of a notch arranged in the inner edge of its flange.

The lid 1 according to the invention (FIGS. 1 to 3) is adapted to be mounted on a container body 2 during the manufacturing of a container 3 (FIG. 1).

This type of container 3 is useful for the packaging of powder foodstuff (also known as “pulverulent foodstuff”).

The container body 2 includes a lateral wall 4, which is herein of circular cross-section (but which could be of any other configuration, size and section).

The material constituting this container body 2, and its method of manufacturing, may be chosen by the one skilled in the art.

For example, the container body 2 is made of metal, in particular steel or aluminium, chosen in particular as a function of the product to be packed.

This container body 2 also includes a bottom wall (not visible), made single-piece with the lateral wall 4 or added on the latter (for example, by seaming).

The lid 1, shown in FIGS. 1 to 3, is herein adapted to be added on this container body 2 of circular cross-section.

This lid 1 could also be adapted to be mounted on a body 2 having another shape/cross-section, for example oval, square, rectangular, oblong, etc.; the general shape thereof would then be adapted accordingly.

As shown in FIG. 1, the lid 1 is hermetically fastened at an end edge 5 of the lateral wall 4 that delimits an upper opening 6 of the container body 2.

This fastening may be made by any suitable technique, for example by seaming.

As shown in FIG. 2, the lid 1 according to the invention comprises (i) a mounting ring (or circle) 10 and (ii) a peelable closing membrane 11, hermetically fixed to said ring 10.

This mounting ring 10 advantageously consists in a metal part, made for example of steel or aluminium.

The shape and size of this ring 10 are adapted as a function of the cross-section of the container body 2 (and in particular of its upper end edge 5) on which it will be mounted.

In this case, this ring 10 has a generally annular or circular shape.

As shown in particular in FIG. 3 (the closing membrane 11 being herein entirely peeled), the ring 10 comprises:

-   -   an outer annular portion 12, adapted to be mechanically fastened         (by seaming, for example) to the end edge 5 of the container         body 2, and     -   an inner portion 13, intended to form a sealing area for the         added closing membrane 11.

The inner portion 13 forms an added flange, herein annular, which is delimited by:

-   -   an inner edge 14, herein annular and defining a central aperture         15,     -   an outer edge 16, connected to the external portion 12 of the         ring 10,     -   an inner face (not visible), intended to be oriented towards the         container body 2, and     -   an upper face 17, intended to be oriented at the opposite of the         container body 2.         The inner 14 and outer 16 edges of the flange 13 herein extend         approximately parallel relative to each other, providing it with         an almost-constant width over its whole circumference.         In particular, the outer edge 16 is circular and centred on a         through-axis A; and the inner edge 14 is circular and slightly         off-centred with respect to this outer edge 16, with an offset         of its through-axis B with respect of the above-mentioned         through-axis A.

The annular flange 13 herein extends in a plane, perpendicular to the top/bottom axis of the lid 1.

According to a not-shown alternative embodiment, this annular flange 13 could also have a generally truncated shape, with its inner edge 14 offset towards the outside (on the side of its upper face 17) with respect to the outer edge 16.

To obtain the release of the internal excess pressure at the initiation of the peeling, the flange 13 of the ring 10 is provided with a passageway 18 for the circulation of gas.

In this embodiment, the passageway 18 consists in several orifices 181 arranged through the flange 13 of the ring 10, between the inner 14 and outer 16 edges thereof.

The orifices 181, herein four in number (but advantageously in a number comprised between 1 and 10), are through-orifices. They each open through the upper 17 and lower faces of the flange 13, to define channels between the internal volume of the container 3 and the external environment.

These orifices 181 are arranged close to each other, along a virtual rectilinear line (but they could also be arranged, for example, on a virtual curved line, or according to an arrangement of the staggered type).

The orifices 181 each have herein a generally circular shape, whose diameter is comprised between 0.5 mm and 1 mm (this shape may be oval, ovoid or elongated).

These orifices 181 thus define together a passageway 18 whose surface area is advantageously comprised between 0.5 and 30 mm².

The closing membrane 11, shown in FIGS. 1 and 2, is for example of the type described in the document EP-1 878 666.

This closing membrane 11 advantageously consists of several superimposed layers, i.e. at least:

-   -   a base layer, made of a flexible and resistant material, forming         a barrier, for example aluminium, and     -   a sealing layer, for example based on polypropylene or of the         sealing varnish type.

This closing membrane 11 may also include any other layer of material, adapted as a function of the desired functionalities (for example an adhesive layer or a layer referred to as “peeling layer”).

This closing membrane 11, also referred to as “membrane seal”, is delimited by (FIG. 2):

-   -   a lower face 20, intended to be oriented towards the container         body 2,     -   an upper face 21, intended to be oriented at the opposite of the         container body 2, and     -   a peripheral outer edge 22 (herein of generally circular shape).

In the continuation of its peripheral edge 22, the closing membrane 11 also includes a pull-tab 23 (or grip-ring) to ensure its manual peeling with respect to the ring 10.

This pull-tab 23 is advantageously made single-piece with the membrane 11, and consists in an extension of material.

As an alternative, the pull-tab 23 is added, directly or indirectly, on the closing membrane 11 (the membrane 11 is then obtained by the assembly of at least two parts).

Before the peeling operation, and conventionally, the pull-tab 23 is advantageously folded opposite and against the upper face 21 of the closing membrane 11 (as very schematically shown in FIG. 3).

According to other embodiments, this closing membrane 11 may be provided with several pull-tabs 23 (at least two), suitably distributed.

The longitudinal axis of symmetry 23′ of this pull-tab 23 (passing between its inner and outer ends) then extends radially, or at least approximately radially (FIG. 3).

The closing membrane 11 is hermetically fixed to the ring 10, advantageously by a link of the bonding and/or welding type (for example, a heat-welding technique), so as to close its central aperture 15.

For that purpose, the outer contour of the lower face 20 of this closing membrane 11 is herein hermetically fastened to the upper face 17 of the annular flange 13 of the ring 10 through a peripheral sealing cord 27.

As illustrated in FIG. 3, this sealing cord 27, herein generally crown-shaped, is delimited by two edges 28, 29 defining between each other the footprint 30 thereof, i.e.:

-   -   an inner edge 28, extending along and on the side of the inner         edge 14 of the flange 13, and     -   an outer edge 29, extending along and on the side of the outer         edge 16 of the flange 13.

This sealing cord 27 thus constitutes an hermetic continuous band, extending over the whole circumference of the associated flange 13.

The inner 28 and outer 29 edges each have herein a generally circular, oval or ovoid shape, extending parallel or at least approximately parallel relative to each other.

At the pull-tab 23, the sealing cord 27 includes a fracture initiation area 31 that is arranged so as to reduce the effort required for initiating its fracture by pulling the tab 23 provided for that purpose, and that thus allows facilitating the initiation of the peeling of the closing membrane 11 with respect to the ring 10.

As shown in FIG. 4, the fracture initiation area 31 of the sealing cord 27 comprises for that purpose an outer protruding section 32 arranged at the outer edge 29.

This protruding section 32 forms a local protuberance with respect to the outer edge 29 of the sealing cord 27, that extends towards the outer edge 16 of the flange 13.

In this case, the protruding section 32 then forms a local protruding portion towards the perimeter, with respect to a virtual continuous line 33 defined by the general shape of the outer edge 29 (FIG. 4).

More precisely, this protruding section 32 of the fracture initiation area 31 has a shape that widens in a direction extending from the outer edge 16 towards the inner edge 14 of the flange 13.

This protruding section 32 has herein a generally point shape, with an outer end 34 arranged at the outer edge 16 of the flange 13 and also at the peripheral edge 22 of the closing membrane 11 that covers it.

This point-shaped protruding section 32 is herein defined by two outer rectilinear, or at least approximately rectilinear, sides 35, which diverge from the outer end 34.

These two divergent outer sides 35 define together an angle 36, advantageously comprised between 60° and 160°.

For an optimum effect, the protruding section 32 of the fracture initiation area 31 has an axis of symmetry 32′ that extends coaxially (or at least approximately coaxially) with respect to the longitudinal axis 23′ of the overlying pull-tab 23 (FIGS. 3 and 4).

To further form the fracture initiation area 31, the inner edge 28 of the sealing cord 27 includes, opposite the above-mentioned outer protruding section 32, a concave section 37 extending towards the outer edge 16 of the flange 13 to form a local recess.

In this case, the protruding section 32 of the outer edge 29 and the concave section 37 of the inner edge 28 of the sealing cord 27 herein form together a fracture initiation area 31 generally chevron-shaped (or reversed-V shaped).

These two sections 32 and 37 are complementary to each other; they extend parallel, or at least approximately parallel, relative to each other.

This particular structure aims to avoid a local widening of the sealing cord 27 at this fracture initiation area 31, with an inherent increase of the force required for the opening.

Within this framework, the passageway 18 of the flange 13 is arranged within the footprint 30 of the sealing cord 27 (between the inner 28 and outer 29 edges of the latter), opposite the pull-tab 23.

More precisely, this passageway 18 is herein arranged within the footprint of the fracture initiation area 31, between the outer 32 and inner 37 portions thereof. In the presence of the passageway 18, this fracture initiation area 31 is herein useful to remedy a possible widening of the sealing cord 27 at this level (this sealing cord widening may be useful to compensate for a possible weakness of the force of fixation).

Moreover, the orifices 181 of this passageway 18 are arranged symmetrically, or at least approximately symmetrically, with respect to the axis 32′ of the fracture initiation area 31 and to the longitudinal axis 23′ of the pull-tab 23 (FIGS. 3 and 4).

Generally, such a fracture initiation area 31 of the sealing cord 27 could be provided on a container 3 whose flange 13 (single-piece or added) could be devoid of any above-mentioned passageway 18.

On the other hand, the flange 13 has advantageously a variable width, with a widened segment 13′ (FIG. 3) at the passageway 18 and, as the case may be, at the fracture initiation area 31, so as to facilitate the arrangement thereof.

For that purpose, as mentioned above, the through-axis B of the inner edge 14 of the flange 13 is herein off-centred with respect to the through-axis A of its outer edge 16, with an offset of its through-axis B at the opposite of this passageway 18 and of this fracture initiation area 31 (FIG. 3).

These through-axes A and B extend advantageously, at least approximately, along the longitudinal axis of symmetry 32′ of the protruding section 32 and of the axis of symmetry 23′ of the pull-tab 23.

The segment 13″ of the flange 13, located at the opposite of the widened segment 13′, thus constitutes the smallest radial width of this flange 13.

In practice, the lid 1 according to the invention is produced on a first site of manufacturing.

For that purpose, the ring 10 and the peelable membrane 11 are manufactured independently of each other by techniques known by the one skilled in the art.

In particular, the passageway(s) 18 can be arranged in the flange 13 of the ring 10 by any suitable machining technique (for example, by drilling, embossing or boring).

These two parts 10 and 11 may then be assembled, for example, by a heat-sealing technique, to form the above-mentioned sealing cord 27.

The particular shape of the sealing cord 27, with its fracture initiation area 31, is obtained for example by means of heat-sealing jaws having a shape adapted for that purpose (for example, from the sealing layer constitutive of the lower face 20 of the closing membrane 11). The outer end 34 of the protruding section 32 is provided on the axis of symmetry 23′ of the tab 23 and at the widened segment 13′ of the flange 13.

During this assembly, the sealing membrane 11 and the ring 10 are moreover suitably oriented relative to each other, so that the pull-tab 23 comes into position at the passageway 18.

As mentioned above, the fracture initiation area 31 is also arranged at the gas passageway 18. The passageway 18 is thus closed by the added closing membrane 11.

The obtained lid 1 can be easily stored and transported to a packaging site, where it is mounted on the container body 2, after the filling thereof with the product. As an alternative, the lid 1 may be mounted immediately on the container body 2, before the transportation of the whole to the product packaging site (the filler site), for the filling thereof by its other open end.

Once the container 3 closed and filled, its opening is operated in a conventional manner; for that purpose, the user has just to suitably pull the tab 23, according to a direction coaxial to its longitudinal axis 23′.

At the beginning of this pulling action, the fracture initiation area 31 allows a reduction of the force and energy required for the degradation of the sealing cord 27, which facilitates the peeling of the closing membrane 11 (due to the flared shape of the protruding section 32 of the fracture initiation area 31).

For that purpose, this pulling action first generates an attack of the outer protruding section 32 of the fracture initiation area 31.

During this initiation of the peeling of the closing membrane 11, the passageway 18 is rapidly cleared, which allows the internal excess pressure of the container 3 to be evacuated before the opening of the central aperture 15 of the lid 1 (the inner edge 28 of the sealing cord 27 being not yet reached by the peeling at that moment). The internal pressure of the container 3 thus balances with the external environment, without spraying or expulsion of the packed product (or at least with a high limitation of this spraying).

The continuation of the pulling action on the tab 23 causes the deterioration of the inner section 37 of the fracture initiation area 31, as well as the remaining length of the sealing cord 27.

The inner aperture 15 is cleared, as the opening 6 of the container 3, offering an access to the packed product.

Another possible embodiment for the ring 10 is illustrated by FIG. 5.

This ring 10 is similar to that described hereinabove in relation with FIGS. 1 to 4, in that it comprises an outer annular portion 12 and a flange 13.

But the flange 13 herein consists of:

(i) an annular peripheral portion 131, on which is shown the sealing cord 27 for the assembly of the closing membrane 11, and (ii) a single-piece disk segment 132, continuing the annular portion 131, on the side of the aperture 15.

The inner edge 14 of the flange 13 thus includes (i) a curved section 141, generally arc-of-a-circle-shaped, and (ii) a local rectilinear section 142, forming the cord thereof.

The local rectilinear section 142 can serve in particular as a scraping surface for levelling a measuring-spoon when the user takes an amount of the packed product.

The disk segment portion 132 is herein solid, i.e. devoid of any passageway 18.

The flange 13 is also different in that it is provided with a plurality of gas passageways 18 regularly distributed over its circumference, within the footprint 30 of its sealing cord 27 (within the annular portion 131).

Each of these passageways 18 consists in a circular orifice 181, similar to that described hereinabove with the embodiment of FIGS. 1 to 4.

This particular structure allows the presence of a passageway 18 under the pull-tab 23 (or approximately under the pull-tab 23), without the obligation of a determined angular orientation of the ring 10 and its membrane 11, during the manufacturing of the lid.

Generally, such passageways 18 could be distributed over a flange 13 whose inner 14 and outer 16 edges extend parallel relative to each other, or at least approximately parallel relative to each other (without the disk segment 132, for example, as defined hereinabove, in relation with FIGS. 1 to 4).

Still another embodiment for the ring 10 is illustrated in FIG. 6.

This ring 10 is similar to that described hereinabove in relation with FIG. 5, in that it comprises an outer annular portion 12 and a flange 13 (including a peripheral annular portion 131 and a disk segment 132).

The passageway 18 is herein similar to that described hereinabove in relation with the embodiment illustrated in FIGS. 1 to 4, i.e. consisted of several circular orifices 181 arranged along a rectilinear line.

The present embodiment is different in that the passageway 18 is arranged within a not-sealed inner area 271 of the sealing cord 27, located within its footprint 30 (between its inner 28 and outer 29 edges). This area 271 is in fact devoid of activated sealing material on the orifices 181, as well as on the perimeter thereof; it herein has a generally oblong or rectangular shape.

This particular structure is interesting to avoid the clogging of the passageway 18 by the material of the sealing cord 27, liable to prevent the release of the internal excess pressure through this passageway 18 at the time of opening.

This particular structure also allows clearing simultaneously the orifices 181, upon opening of the not-sealed inner area 271.

Still another embodiment for the ring 10 is illustrated by FIG. 7.

This ring 10 is also similar to that described hereinabove in relation with FIG. 7, with the gas passageway 18 arranged within a non-sealed inner area 271 and within the footprint 30 of the sealing cord 27.

The passageway 18 is herein different in that it consists in a single slot-shaped orifice 181, whose length is for example comprised between 10 and 20 mm and whose width is advantageously comprised between 0.5 and 3 mm. The area 271 devoid of activated sealing material has here also a general oblong or rectangular shape.

The longitudinal axis of this slot 181 is herein rectilinear, but it could have a curvature parallel to the outer edge 16 of the flange 13.

FIG. 8 shows an alternative embodiment of the ring 10 according to FIGS. 1 to 4

There is still the ring 10 carrying a sealing cord 27 having a fracture initiation area 31 provided with a protruding section 32 at its outer edge 29 and with a concave section 37 at its inner edge 28.

In this embodiment, the passageway 18 consists in a circular orifice 181 arranged on the flange 13, between the inner edge 28 of the sealing cord 27 and the inner edge 14 of said flange 13, in this case within its concave section 37.

Here again, this embodiment aims to limit the risk of clogging of the passageway 18 by the material of the sealing cord 27.

In practice, this embodiment needs the complete degradation of the fracture initiation area 31 to allow the travel of the inner gas of the container 3 (in excess pressure) through the passageway 18 provided for that purpose, before the clearing of the inner aperture 15.

Here again, it is advisable to continue the peeling of the closing membrane 11 to open the central aperture 15.

FIG. 9 also shows an alternative embodiment of the ring 10 according to FIGS. 1 to 4.

In this embodiment, the ring 10 also carries a sealing cord 27 having a fracture initiation area 31 provided with a protruding section 32 at its outer edge 29 and with a concave section 37 at its inner edge 28.

The passageway 18 herein consists in a notch 182 arranged from the inner edge 14 of the flange 13 of the ring 10 and extending towards its outer edge 16. In other words, this notch 182 defines a passageway for the circulation of gas (continuing the central aperture 15), taking into account a virtual continuous line 143 defined by the general shape of the inner edge 14 of the flange 13.

The notch 182 herein fits with the concave section 37 of the fracture initiation area 31.

According to an alternative embodiment, this notch-shaped passageway 18 could be adapted on any other form of sealing cord 27 (possibly devoid of a fracture initiation area 31).

In practice, as described hereinabove, in relation with FIG. 8, this embodiment also requires the complete degradation of the fracture initiation area 31 to allow the travel of the inner gas of the container 3 (in excess of pressure) through the passageway 18 provided for that purpose.

Here again, it is advisable to continue the peeling of the sealing membrane 11 to open the central aperture 15.

Generally, the lid according to the invention thus allows a release of the internal excess pressure of a container at the initiation of the opening, before the clearing of its central aperture, thus eliminating the risks of expulsion or spraying of the packed product.

According to an embodiment not shown, the closing membrane is added on the container by a so-called “direct heat-sealing” technique.

Within this framework, the flange 13 is made single-piece with the lateral wall 4 of the container body 2.

The outer edge 16 of this flange 13 is hence connected, by at least one single-piece folding line, with the end edge 5 of this lateral wall 4.

Such a container is for example made by embossing a metal blank, for the formation of a tubular lateral wall connected to a bottom wall, out of which is cut a central portion so as to obtain the central aperture lined with the single-piece flange.

The gas passageway(s) are suitably arranged in this flange, before or after the cutting of the central portion.

The peelable closing membrane is then suitably added on this single-piece flange by heat-sealing, before the filling with the product to be packed and the closing of the opposite opening.

According to an alternative embodiment, the container body is made single-piece, for example (i) by embossing a metal blank, for the formation of a tubular lateral wall connected to a bottom wall, and (ii) by rolling and/or embossing the free edge of the tubular lateral wall to form the single-piece flange.

The gas passageway(s) are suitably arranged in this flange, before or after its formation.

The peeling closing membrane is suitably added on this single-piece flange by heat-sealing, after the filling with the product to be packed. 

1. A container intended to receive a powder product and intended to have an internal excess pressure, said container (3) comprises: (i) a flange-shaped inner portion (13), intended to extend on the perimeter of an opening (6) to be closed, which flange (13) is delimited by a lower face, an upper face (17), an inner edge (14) defining a central aperture (15) and an outer edge (16) connected to a lateral wall (4) of the container body (2), and (ii) a peelable closing membrane (11) intended to close said central aperture (15), including an upper face (21) and a lower face (20), wherein the outer contour of the lower face (20) is hermetically fixed to the upper face (17) of said flange (13) through a sealing cord (27), which closing membrane (11) is provided with at least one pull-tab (23) to allow the peeling thereof with respect to said flange (13) by degradation of said sealing cord (27), characterized in that said flange (13) is provided with at least one passageway (18) for the circulation of gas, which passageway (18) is intended to be closed by said added closing membrane (11) and is located opposite said pull-tab (23) to release the internal excess pressure of the container (3) upon the initiation of the peeling of said closing membrane (11).
 2. The container according to claim 1, characterized in that said passageway (18) consists in at least one orifice (181) arranged through the flange (13), between its inner (14) and outer (16) edges.
 3. The container according to claim 2, characterized in that the orifice(s) (181) define together a passageway (18) whose surface area is comprised between 0.5 and 30 mm².
 4. The container according to claim 2, characterized in that the orifice(s) (181) have a generally circular shape, whose diameter is comprised between 0.5 and 1 mm, and are 1 to 10 in number.
 5. The container according to claim 2, characterized in that the orifice(s) (181) consist in an elongated slot, whose length is comprised between 10 and 20 mm and whose width is comprised between 0.5 and 3 mm.
 6. The container according to claim 2, characterized in that the orifice(s) (181) arranged in the flange (13) are located within the footprint (30) of the sealing cord (27).
 7. The container according to claim 6, characterized in that the sealing cord (27) includes at least one not-sealed inner area (271), and in that the orifice(s) (181) are arranged in said non-sealed inner area (271).
 8. The container according to claim 2, characterized in that said passageway (18) is arranged between an inner edge (28) of the sealing cord (27) and an inner edge (14) of the flange (13).
 9. The container according to claim 1, characterized in that said passageway (18) consists in a notch (182) arranged from said inner edge (14) of the flange (13) and extending towards its outer edge (16).
 10. The container according to claim 1, characterized in that the flange (13) includes several passageways (18) that are regularly distributed over its circumference.
 11. The container according to claim 1, characterized in that the inner (14) and outer (16) edges of the flange (13) extend parallel, or approximately parallel, relative to each other, providing it with a constant or approximately constant width over its whole periphery.
 12. The container according to claim 1, characterized in that the flange (13) consists of a peripheral annular portion (131) continued by a disk segment (132).
 13. The container according to claim 1, characterized in that the peripheral sealing cord (27) is delimited by an inner edge (28) and an outer edge (29), and in that said sealing cord (27) includes a fracture initiation area (31) arranged at said pull-tab (23), which fracture initiation area (31) comprises a protruding section (32) of said outer edge (29) of said sealing cord (27) that forms a local protuberance extending towards said outer edge (16) of said flange (13), to reduce the effort required for initiating the fracture of said sealing cord (27) by pulling the tab (23) and thus facilitating the initiation of the peeling of said closing membrane (11), and in that at least one of the passageways (18) is arranged at said fracture initiation area (31).
 14. The container according to claim 1, characterized in that: (i) the flange (13) is made single-piece with the lateral wall (4) of the container body (2), or (ii) the container (3) is provided with an added ring (10) including—an outer portion (12), fixed on an edge (5) of the container body (2) delimiting said opening (6) to be closed, and—an inner portion (13) forming an added flange, intended to extend over the perimeter of said opening (6) to be closed.
 15. A ring for a lid (1) intended to equip a container body (2), possibly equipped with a peelable closing membrane (11), according to claim
 1. 16. The container according to claim 3, characterized in that the orifice(s) (181) have a generally circular shape, whose diameter is comprised between 0.5 and 1 mm, and are 1 to 10 in number.
 17. The container according to claim 3, characterized in that the orifice(s) (181) consist in an elongated slot, whose length is comprised between 10 and 20 mm and whose width is comprised between 0.5 and 3 mm. 